SIG Sauer SIGM400
| SIG Sauer SIGM400 series | |
|---|---|
Sig Sauer M400 series rifle  | |
| Type | Semi-automatic rifle Carbine  | 
| Place of origin | United States | 
| Service history | |
| In service | 2010–Present | 
| Used by | See Users | 
| Wars | War in Iraq (2013–2017) Islamic State insurgency in Iraq (2017–present)  | 
| Production history | |
| Designed | 2000s | 
| Manufacturer | SIG Sauer | 
| Produced | 2010–Present | 
| Specifications | |
| Mass | 7.6 pounds (3.4 kg) | 
| Barrel length | 14.5–20 inches (37–51 cm) (5.56×45mm) 9–16 inches (23–41 cm) (.300 AAC)  | 
| Cartridge | 5.56×45mm NATO .223 Remington .300 AAC Blackout  | 
| Action | Direct gas impingement system, rotating bolt | 
| Feed system | STANAG magazines | 
The SIGM400 is a family of firearms manufactured by SIG Sauer. The M400 is an air-cooled, direct impingement gas-operated, magazine-fed carbine that is based on the earlier AR-15 rifle. Depending on the variant, it can be chambered for 5.56×45mm NATO or .300 AAC Blackout cartridges, and may have a fixed or telescoping stock.